1. Field of the Invention
The present invention relates generally to camera lenses, and more particularly, to a low-aberration compact lens assembly.
2. Description of the Related Art
As the digital cameras have been popular and numerously applied to various kinds of electronic products, requirement of the electronic products for high quality and miniaturization is also applied to the built-in lens assembly of the digital cameras. In consideration of compactness and effectively overcoming a variety of aberrations for the overall optical imaging, the lens of the digital camera is not only usually made of resin material, which is transparent to visible light, to be lighter than the lens made of glass, but also possessed of good plasticity for production of a variety of aspheric lenses, such that a compact lens assembly having less lens groups but the optimum quality for image pickup under required optical conditions can be fulfilled.
As for a lens for image pickup disclosed in China Patent Application No. 200410002504.3 filed by Milestone Co., Ltd. and a single-focus lens disclosed in China Patent Application No. 200510055986.3 filed by Fujinon Corporation, each of them is composed of two lenses, in which the surface of each lens is aspheric. When a specific condition is satisfied for each lens, the aspheric surfaces can correct the aberrations of the overall optical image forming, like chromatic aberration, spherical aberration, comatic aberration, field curvature, distortion, and astigmatism, to fulfill the best quality.
However, compared with the general spherical lens in practice, the surfaces of the aspheric lens made of resin are of variations of high-precise geometrical conditions. Under the circumstances, the abrasive and polishing approaches for production of the aspheric lens in low temperature are highly sensitive to process operations, such that the more the aspheric lenses the lenses are required, the more complex the production engineering of the lenses is and the higher the production cost is.